Culture of cells, e.g., mammalian cells or insect cells, for in vitro experiments or ex vivo culture for administration to a human or animal is an important tool for the study and treatment of human diseases. Cell culture is widely used for the production of various biologically active products, such as viral vaccines, monoclonal antibodies, polypeptide growth factors, hormones, enzymes and tumor specific antigens. However, many of the media or methods used to culture the cells comprise components that can have negative effects on cell growth and/or maintenance of an undifferentiated cell culture. For example, mammalian or insect cell culture media is often supplemented with blood-derived serum, such as fetal calf serum (FCS) or fetal bovine serum (FBS) in order to provide growth factors, carrier proteins, attachment and spreading factors, nutrients and trace elements that promote proliferation and growth of cells in culture. However, the factors found in FCS or FBS, such as transforming growth factor (TGF) beta or retinoic acid, can promote differentiation of certain cell types (Ke et al., Am J Pathol. 137:833-43, 1990) or initiate unintended downstream signaling in the cells that promotes unwanted cellular activity in culture (Veldhoen et al., Nat Immunol. 7(11):1151-6, 2006).
The uncharacterized nature of the serum composition and lot-to-lot variation of the serum make use of a serum replacement and culture in serum-free media desirable (Pei et al., Arch Androl. 49(5):331-42, 2003). Moreover, for cells, recombinant proteins or vaccines for therapeutic use that are grown in cell culture, the addition of animal-derived components is undesirable due to potential virus contamination and/or to the potential immunogenic effect of the animal proteins when administered to humans.
Serum replacements have been developed in attempts to minimize the effects of FCS on cell culture, as well as minimize the amount of animal protein used for culture of human cells. Serum replacement, such as KNOCKOUT™ serum replacement (Invitrogen, Carlsbad, Calif.), is termed a chemically defined culture medium, lacking serum and containing essential nutrients and other proteins for cell growth. KNOCKOUT SR™ cannot be used as a replacement for FBS in the plating of feeder cells due to the lack of attachment factors, which results in inadequate cell attachment in this formulation. PC-1™ serum free media (Lonza, Walkersville, Md.) is a low-protein, serum-free medium formulated in a specially modified DMEM/F12 media base and contains a complete HEPES buffering system with known amounts of insulin, transferrin, fatty acids and proprietary proteins.
Cellgro COMPLETE™ (Cellgro, Manassas, Va.) is a serum-free, low-protein culture media based on a mix of DMEM/F12, RPMI 1640 and McCoy's 5A base mediums. Cellgro COMPLETE™ does not contain insulin, transferrin, cholesterol, growth or attachment factors, but comprises a mixture of trace elements and high molecular weight carbohydrates, extra vitamins, a non-animal protein source, and bovine serum albumin.
Serum-free medias are also described in International Patent Publication Nos. WO2009023194, WO2008137641, WO2006017370, WO2001011011, WO2007071389, WO2007016366, WO2006045064, WO2003064598, WO2001011011, US Patent Publication Nos. US20050037492, US20080113433, US20080299540, U.S. Pat. Nos. 4,560,655, 5,324,666, 6,162,643, 6,103,529, 6,048,728, 7,709,229 and European Patent Application No. EP2243827.
U.S. Pat. No. 7,220,538 describes a cell culture media comprising lipophilic nanoparticles and base nutritive media.